Burr



FIG. 1 is a perspective view of a burr in accordance with the present invention;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevation view thereof; and,

FIG. 4 is a side elevation view thereof.

The broken lines shown in the figures represent portions of the burr that form no part of the claimed design. 

CLAIM The ornamental design for a burr, as shown and described. 